Starter gearing



April 20, 1954 E. M. oRBEcK STARTER' GEARING INVENTOR 'A E/NAR M.OBECI(` ATTORNEY Patented Apr. 20,I 1954 UNITED STARTER GEARING Einar M.Orbeck, West Hartford, Conn., assignor to United Aircraft Corporation,East Hartford, Conn., a corporation of Delaware Application July 5,1952, Serial No. 297,228

(Cl. 'ift-7) 6 Claims.

This invention relates to starters and more specifically to pneumaticstarters for high speed power plants.

It is an object of this invention to provide a turbine-driven starterfor power plants requiring high starting speeds.

Itis another object of this invention to provide a starter of the typedescribed including a clutching mechanism contained within the starterhousing. These and other objects of this invention will become readilyapparent from the following detail description of the drawing whichillustrates a cross-sectional view of the starter of this invention withportions of the cross section being taken in several different planes soas to fully show the parts.

Referring to the drawing, the starter coinprises a power sectiongenerally indicated at l0,

a reduction unit l2, a clutch unit I4 and a member I5 for driving thepower plant. The power unit l0 comprises an intake opening 20 whichleads to an annular chamber 22 and into which pressurized gases areadmitted. The gases may be compressed air, high temperature combustionproducts or gases from any form of gas generator. The fluid from chamber22 passes through a plurality of nozzles 24 from where it is directedagainst the blades 26 of a turbine rotor 28. After leaving the turbinethe gases may escape via the central opening 30. The turbine rotor 28forms an integral part of a shaft 32 which is mounted centrally of thestarter by means of a ball bearing unit 30.

A sleeve 40 surrounds the shaft 32 and is fixed relative thereto bymeans of a nut 42. The sleeve t0 includes integral teeth t0 which engagethe teeth of two gears, one of which is indicated at 430. Another gearsuch as 15B engages the teeth :it at a diametrically opposite point. Theother gear is not illustrated herein since the drawing shows a crosssection which is taken in several planes. The gear 40 and its companion5t are mounted on a shaft 48 which in turn rotatably mounted in ballbearings 50 and 52. Again, as mentioned in connection with the gearthere are two diametrically opposite shafts which are identical but onlyone of the shafts shown. The gear 56?' engages one of two gears euch. as52 each of which is carried by a separate countershaft 00. Again, asmentioned previously, there are two shafts such as 50 diametricallyopposite each other but only one is shown. The shaft 50 is mounted atone end in a double set of ball bearings 0d which are carried by thecasing portion Se?. The shaft t0 is also supported intermediate vitsends by another set of double hall bearings S2 which are carried withinthe casing portion 70 by housing 1|.

The right-hand end of the` shaft t0 carries integra?. helical gear teeth30k which lare adapted to engage cooperating Vhelical".teeth,,'82carried by the gear 04. The shafts such as 00 at their left-hand end areengaged by a stack of Belleville springs 90. These springs a'ct topermit axial movement of the shaft 60 so as to permit equalization ofthe loads between the two gear trains, bearings 68 and the adjacent casel0, and the bearings 04 relative to the adjacent casing 60.

The gear 00 has an internal high pitch thread |00 which mates with acorresponding thread carried by a sleeve |02. rI'he 4gear 84 and thesleeve |02 are urged in the position shown by means of a spring |04. ABelleville spring or washer |05 engages the left-hand end of the sleeve|02 and acts as a friction member which tends to restrain the sleeve |02against rotation since the sleeve |02 is mounted on shaft H0 by means ofa set of ball hearings ||2 and IH.

When pressurized gases cause rotation of the turbine rotor 20 which bymeans of the gear train. described previously rotates the shaft 00 whichin turn tends to rotate gear 34, the sleeve |02 will tend to berestrained by the friction of the Belleville washer |00 so as to causethe gear Sd by reason of the high lead thread |00 to ad- Vance towardthe right against the pressure of spring |02 so that its clutch teeth|20 will begin to engage with the clutch teeth |22 which are carried byannular flange |20 formed integral with the shaft ||0. When the clutchteeth |20 and |22 first engage, the load when transmitted back to thehelical teeth and 82 will cause more positive engaging force to beapplied to the clutch teeth |20. In other words, the relative angles ofthe helical teeth 30 and 82 are such that under load the gear 04 willtend to move to the right.

Upon engagement of the teeth |20 and |22 the shaft H0 will be caused torotate so as to drive the element l0 which in turn is in continuousengagement with a member |30 carried by a fixed portion |32 of the powerplant proper. The element |30 is rotatable within the xed portion |32and carries a gear |30 adapted to engage the driving shaft of the powerplant, l

The shaft H0 is mounted within a starter casing l0 by means of a ballbearing |40 adjacent the right-hand end of the shaft and a double set ofball bearings |62. Thus it can be seen that the shaft H0 will rotatecontinuously duringr operation of the power plant while the clutch teeth|20 and i 22 will be engaged and disengaged upon control of the uidwhich tends to .rotate the turbine 22. In other words, as the powerplant gets up to speed the duid supplied to the inlet 20 will be cut offand the various gears of the starter will decelerate so that eventuallythe spring Mld will return the gear 8:1 to the disengaged positionillustrated. YSeals such Yas |50 adjacent the right-hand side of thecasing' and 352 adjacent the turbine end of the Casin-ginsure that thearea internally of the entire starter casing is fluid tight. A lleropening (not illustrated) is provided so that a certain level oflubricating oil can be maintained within the starter housing. Underthese conditions the gears 46 and 58 dip into the oil so that a mistVlubrication is provided. When the main power plant is operating and thestarter gears are stationary, a splasher plate i6@ carried by the annular flange IE; of the shaft lili provides adequate lubrication. Inother words, since the shaft l l0 is rotating during the operation ofthe power plant the disc itil will dip into the oil` and distributesufficient lubrication which will be particularly needed for thebearings M9 and M2 which'support the shaft llt and also bearings H2 andlill. In order to preload the bearings which support the turbine shaft32 and the shaft H0 a spring ft2 is provided at the adjacent ends ofthese shafts forcing them in opposite directions.

As a result of this invention it is apparent that a compact and ruggedstarter has been provided which can transmit high power through its gearreduction mechanism while doing so under load equalized conditions.Hence, it is apparent that manufacturing tolerances and the like willnot have a deleterious effect on wearing qualities of the several parts.and engaging elements of the starter are completely housed within itscasing so that the starter can be mounted on and engaged to the powerplant by a simple standard splined connection.

It should also be noted that with the type of gear train described,initial load difference between each train may be in the order of a40-60 ratio. Therefore, since the helical splines at the end of shaftSi) causes the pressure on Belleville Furthermore, the clutching springSil to be directly related to the torque carried by the shaft the shaftcarrying the heavier load will tend to wear more rapidly. As a result,the loads will tend to equalize as wear progresses.

Although only one embodiment of this invention has been illustrated anddescribed herein it will be Iapparent that various changes andmodifications can be made in the construction and arrangement of thevarious parts without departing from the scope of this novel concept.

What it is desired to obtain by Letters Patent is:

1. In a starter for a rotary member, :a rotary driving element, a memberdriven by said elementand adapted to be moved along its axis forengagement with the rotary member, cooperating mechanism for drivablyconnecting said members upon engagement thereof, a sleeve -coaxiallydisposed within said driven member including spiral teeth engagingcooperating teeth Yon an internal surface of said driven member, andmeans for restraining said sleeve against rotation to cause relativeaxial movement of said driven member.

2. In a starter for a rotary member, a rotary driving element, a memberdriven by said element and adapted to be moved along its axis forengagement with the rotary member, cooperating mechanism for drivablyconnecting said members upon engagement thereof, said driven memberincluding an internal surface having teeth carried thereby, a sleevecoaxially disposed within said driven member including spiral teethcooperatively engaging the teeth on the internal surface of said drivenmember, resllient means urging said driven member in one 4 axialdirection relative to said sleeve, and means for restraining said sleeveagainst rotation to cause relative axial movement of said driven memberin another axial direction for engagement with said rotary memberincluding friction means having continuous engagement with said sleeve.

3. In a starter for an internal combustion power plant having an elementto be driven by the starter, a power device for energizing the starterincluding a rotatable member having helical teeth, a second memberhaving helical teeth and engaging said first member for rotationtherewith, a shaft including a third member to be engaged and driven bysaid second member, cooperating mechanism drivably connecting saidsecond and third members upon engagement thereof, means for engagingsaidV second and third members upon energization of the starter, saidhelical teeth urging further engagement of said second and third membersupon initial engagement thereof due to loads imposed thereupon, ahousing enclosing said members including a journal for said shaft, andmeans exter-Y nally of said housing and carried by said shaft having acontinuous engagement with said element,

4. In a starter according to claim 3 wherein said means for engagingcomprises a sleeve fixed against axial movement having a thread engagingsaid second member, and friction means for restraining rotation of saidsleeve to induce axial motion of said second member.

-5. In a clutch device for a starter having a rotatable driving member,said driving member being hollow and having internal threads, means forrotating said driving member, a shaft having one end engageable with anelement to be rotated, a dog member fixed intermediate the ends of saidshaft adapted to be engaged by said driving member, a sleeve freelymounted on the other end of said shaft, external threads on said sleeveengaging said internal threads, means carried by said driving member forengaging said dog member, said driving member being adapted toad- Vancealong the axis of said shaft relative to said sleeve and engage saiddog, resilient means vurging said driving member toward disengagedposition, and friction means engaging said sleeve to hinder rotationthereof whereby said driving member advances relative to said sleeve toengage said dog upon rotation thereof so as toV rotate said shaft.

6. In a starter for an internal combustion power yplant having anelement to be driven by the starter, a power device for energizing thestarter, a toothed member operatively connected to and driven by saiddevice, a shaft including a member to be engaged by said toothed member,cooperating mechanism for drivably connecting said members uponengagement thereof, means for engaging said members `upon energizationof the starter, a housing enclosing said members including a journal forsaid shaft, and means externally of said housing and carried by saidshaft having a continuous engagement with said element.

References cited in the fue of'tmspatent UNITED srA'rEs PATEN'rs

